The present invention relates generally to roadside or roadway barriers used to prevent vehicles from crossing from the lane of traffic that they are traveling in to an opposite or adjacent lane, carrying vehicles traveling in an opposite direction. The present invention also relates to barrier modules which prevent vehicles from entering into any hazardous area on the roadway. In this manner, roadway barriers prevent head-on collisions on the highways and collisions with other hazardous objects. The present invention also relates to roadside barriers which prevent vehicles from leaving the highway and colliding with fixed roadside obstacles.
Specifically, the present invention relates to an improvement in the end treatment of a concrete barrier wall. The apparatus according to the present invention is specifically designed to reduce the chances of serious injury to the occupants of a vehicle which impacts an end of a concrete barrier wall.
The primary function of a concrete barrier wall is to redirect errant vehicles back into the flow of traffic without allowing the vehicle to leave the roadway or cross into oncoming lanes of traffic. Further, the barrier should redirect the errant vehicle without seriously injuring the occupants of the vehicle. Secondarily, the barrier should also protect against collisions with roadside obstructions, which may be power poles or bridge abutments. Protection of the obstruction may also be important, for a power pole downed by an errant vehicle may mean a loss of electrical power for large numbers of people. Similarly, a damaged bridge abutment is very costly to repair and may mean closed thoroughfares until the damage has been repaired. Most importantly, however, concrete barriers prevent loss of life caused by "head-on" collisions between vehicles. And, although known prior art barriers have accomplished these objectives, they have all been marked by a common, serious disadvantage. The blunt end of the concrete barrier, facing the oncoming traffic, has proven to be very hazardous.
Typically, the end of a concrete barrier wall has been either a blunt, fist shaped end; a blunt end protected by a disposable, "single-event" cushion; or an end protected by a sloping concrete or metal guardrail end-treatment. All of these known barrier wall end-treatments have proven to be unsatisfactory, either for economic or functional reasons.
The known blunt end-treatments for concrete barrier walls have proven to be unsatisfactory because a vehicle impacting the blunt end "head-on", is stopped so abruptly that the occupants of the vehicle are most often severely injured or even killed. In a similar manner, many disposable "single-event" cushions used to protect these blunt barrier wall ends have proven to be ineffectual for the same reason. Further, other known "single-event" cushions have proven to be unsatisfactory because they are only partially effective when a vehicle impacts the end of a barrier wall at a high rate of speed. The few known "single-event" cushions that do perform well are extremely costly.
Finally, concrete or metal guardrail end-treatments, which provide a top surface which slopes gently from the ground up to the top of the concrete barrier wall, often cause severe injury to the occupants of a vehicle which, when encountering these sloping end treatments, ramps up onto the end treatment and is guided directly to the top of the concrete barrier wall where the concrete barrier wall acts as a rail which will often either: (a) cause the vehicle to roll, thereby causing injury to the occupants of the vehicle; or (b) guide the errant vehicle directly into a roadside obstacle, thereby severely injuring the occupants of the vehicle when the vehicle impacts the obstacle.
The known concrete barrier wall end-treatments of the prior art, therefore, have all been distinguished by fundamental drawback: they are unable to deaccelerate a vehicle impacting the end of a concrete barrier wall in such a manner so as to avoid serious injury to the occupants, or they do so at a cost that is unreasonable from societal investment standpoint.